Communication devices, such as cellular telephones, have become increasingly versatile and are not longer used only for making and receiving phone calls. The applications of today include for example applications that allow users to do as send/receive text messages, play games, watch TV, play music, take pictures, etc. As a result, cellular telephones are part of every day life and are therefore carried around by the user in some convenient way. Usually it is carried in a pocket, in a special case attached to a belt or similar, in a handbag, a backpack or the like.
Since the cellular phone is carried around it is also often exposed to noisy environments. This might cause a problem when the cellular phone is ringing or activated in some other way. It may be difficult for a user to perceive such a signal on time in order to respond to it due to the background noise.
Most cellular phones therefore include some mechanisms for adjusting the volume of the ring signal in response to the noise of the surrounding environment. One way is to provide the cellular phone with a user interface that defines different user profiles, which each define the type of ring signal to be used depending on the situation the user is in, such as a loud ring signal, a vibrating signal etc. Such user profile may be set manually by the user, for example putting the cellular phone in vibrating mode when selecting the profile “meeting”.
One other solution to this problem could of course be to constantly keep the ring signal at a high level. However, loud ring volumes may cause hearing damages and also tend to be very disturbing in quiet environments. Maximum allowed ring signals are therefore regulated by cellular phone standards.
Another way to adapt the ring signal is to first check the input level of the microphone, i.e. high for a noisy environment and low for a quiet environment, and adapting the ring signal level in response thereto.
However, this method does not work very well when the device is carried in a pocket, bag or the like since the noise picked up by the microphone may by damped by the surrounding in which the cellular phone is kept, which makes the emitted ring signal softer. What makes this situation even more problematic is that the same muffling effect that damps the surrounding noise also will dampen the already soft ring signal even more. This will result in a risk that the user completely misses the call.